1. Field of the Invention
The present invention relates to impact scrubbers for removing coating materials from the surface of particulate matter. More particularly, a new and improved scrubber is especially designed for removing coatings of binding materials from spent foundry sand and the like. The impact scrubber of the invention is also useful in treating a wide variety of other particulate materials which have unwanted coatings of material thereon which are removed by impact and are then separated from the main particles because of their lighter weight.
2. Description of the Prior Art
U.S. Pat. Nos. 2,813,318; 3,088,183; 3,825,190 and 3,907,213 disclose impact type sand scrubbers useful in the reclamation of spent foundry sand. These patents are owned by the same assignee as the present application and the invention shown and described herein constitutes an improved impact scrubber for the removal of coating materials from the surface of particulate matter.
It is an object of the present invention to provide a new and improved impact scrubber for removing coating materials from the surfaces of the particulate matter, such as foundry sand and the like.
More specifically it is an object of the invention to provide a new and improved impact scrubber which is especially well suited for removing binders and other coating materials from spent foundry sand and the like.
Another object of the present invention is to provide a new and improved impact scrubber of the character described which is highly efficient in operation, relatively low in cost, relatively low in cost of operation and which requires a minimal amount of servicing and maintenance.
Yet another object of the present invention is to provide a new and improved impact scrubber of the character described which employs a secondary fluid stream for effecting separation of the coating materials which are removed from the base particulate matter.
Yet another object of the present invention is to provide a new and improved impact scrubber having means for adjustably controlling the sand flow and the secondary air flow which remove the lighter fines from the particulate matter that is being cleaned.
Still another object of the present invention is to provide a new and improved impact scrubber of the character described having a plurality of operating units or cells operatively connected in series with novel baffle means for dividing the output of one cell between an imput flow to the next cell and a recycle flow which is returned to the same cell for further treatment.
Yet another object of the present invention is to provide a new and improved impact scrubber of the character described having novel flow control means for discharging the cleaned or finished product at a prescribed flow rate.
Yet another object of the present invention is to provide a new and improved impact scrubber of the character described which requires a minimal volume of fluid flow yet provides exceptional quality and control and is extremely efficient in separating the unwanted coating materials from the base particulate matter.
Still another object of the present invention is to provide a new and improved impact scrubber of the character described which employs both a primary and a secondary fluid system for more efficient operation.
Still another object of the present invention is to provide a new and improved impact scrubbing device of the character described wherein a primary air or fluid flow is utilized for impacting the material against a target and a secondary fluid or air flow is utilized for separating the unwanted coating materials from the base particulate matter.
Yet another object of the present invention is to provide a new and improved impact scrubber for granular material and the like which requires a much lesser volume of air flow per pound of product handled than heretofore thought possible.
Still another object of the present invention is to provide a new and improved impact scrubber which can be tuned and adjusted to provide maximum scrubbing action with a minimum amount of energy expanded per unit of material being treated.
Yet another object of the present invention is to provide a new and improved impact scrubber of the character described which requires a lesser volume of high pressure primary fluid flow by providing an adjustably controllable secondary air flow at lower pressure for removal of the unwanted coating materials from the base product.
Another object of the present invention is to provide a new and improved impact scrubber which has a much lower operating expense than theretofore thought possible and which requires less maintenance and servicing because of improved design and reduced wear characteristics.